Recently, with the rapid development of microwave communication technologies such as mobile communication and satellite communication technologies, there is an increasing demand for microwave dielectric ceramics which are widely utilized in dielectric resonators, dielectric filters, dielectric antennas, and any of various microwave electronic components. The rapid developing trend that higher frequencies are utilized in microwave communication sets higher requirements for low-loss microwave dielectric ceramics, wherein three principle characteristics are: dielectric constant ε<30, in order to be suitable for applications at higher frequencies; quality factor Qf>60,000 GHz, to obtain better frequency selectivity; temperature coefficient of resonant frequency τf=0±10 ppm/° C., to ensure the stability of components when the operating temperature fluctuates.
On the other hand, exemplary low-loss microwave dielectric ceramics hitherto known are Ba(Mg1/3Ta2/3)O3, CaTiO3—MgTiO3, et al. The former have some shortcomings such as high sintering temperature, long-time heat treatment, high sensitivity of the quality factor and temperature coefficient of resonant frequency to the processing conditions, whereas the latter has the disadvantage of a relatively low Qf value. Besides, the former costs too high due to the noble constituent element, Ta.
Therefore, there is an urgent need to develop a microwave dielectric ceramic which has combined merits of easy-preparing, low-cost, and high performance to satisfied relevant application requirements.